4N25/4N28 Phototransistor Optocoupler – NPN Si / GaAs (JAYCAR)

You need signal isolation with a phototransistor output, not just a bare LED-to-LED pair. The 4N25 through 4N28 series pairs an NPN silicon planar phototransistor with a gallium arsenide emitter diode. Optically coupled. No electrical connection between input and output. If your schematic calls for one of these four variants, it's on the shelf

• NPN silicon planar phototransistor output
• Gallium arsenide (GaAs) emitter diode
• Covers 4N25, 4N26, 4N27 and 4N28 variants
• Optical coupling – no direct electrical path between sides